The present disclosure relates generally to microdevices and, more specifically, to microlenses.
Microlens arrays are widely employed in image sensor technology, such as charged coupling device (CCD) image sensors and complimentary metal-oxide-semiconductor (CMOS) image sensors. In general, CCD, CMOS, and other types of microlens arrays transform a light pattern (e.g., a pixel image) into an electric charge pattern.
Microlens arrays generally include polymer or dielectric microlenses. Polymer microlenses can be formed by patterning a polymer layer and subsequently thermal reflowing the patterned polymer layer to create the required shape of each microlens.
However, when pixel size is decreased and/or microlens packing density is increased, the processing window for creating and using the microlens arrays is narrowed down accordingly. As a result, process operations can become more difficult. For example, a thermal reflow process can become problematic due to the potential merging of neighboring microlenses.